The Miami Dolphins are coming off back-to-back 8-8 seasons and enter a playoff-or-bust year in 2015. In order to accomplish that goal, they must fill several key needs.

ESPN.com's Dolphins page continues its rankings of Miami’s top-5 needs.

No. 2: Defensive tackle

2014 starters: Randy Starks, Jared Odrick

Top free agents: Ndamukong Suh, Letroy Guion, Ahtyba Rubin

Why it’s an issue: Odrick is an unrestricted free agent and Starks, 31, showed signs of slowing down last season and is getting long in the tooth. Even with both players, Miami’s run defense was ranked 24th in the NFL allowing 121.1 yards per game and completely collapsed in the second half of the season. I don’t expect Odrick to return to Miami. He’s a “tweener” who doesn’t quite fit Miami’s 4-3 defense. Odrick was moved from defensive end to defensive tackle two seasons ago, but he wasn’t dominant at either position. He would be a great fit as a 3-4 defensive end, and that is where Odrick could draw interest. Starks also could be a salary-cap casualty. He’s due $5 million next season, and the Dolphins must decide if he’s worth keeping around.

Walker’s solution: It’s easy to say go get Suh, who would quickly solve this issue. But the Dolphins would be hard-pressed to come up with the kind of money Suh will command on the open market. I would let Odrick sign with another team where he’s a better fit and consider cutting Starks based on what’s available in the draft and elsewhere in free agency. Earl Mitchell was a co-starter last season and rotated pretty heavily with Starks and Odrick. He should get more reps in 2015. The Dolphins also should consider a defensive tackle with the No. 14 pick in April’s NFL draft. I really like Washington defensive tackle Danny Shelton for that pick if he’s available.